Yes, they are prewounds. Aside from the paper, though, you have to make sure they're the right size for your machine. The wide flat ones say Class F, and I don't know any domestic machines that use that class of bobbin.
The smaller, taller ones with white thread look like they might be class 15, which is used by many Janomes, Kenmores, Brothers, and of course the Singer model 15 machines. Measure and compare the size to a bobbin that you know works before trying it.